This invention relates generally to the field of water purification, and more particularly to antimicrobial systems for the purification of drinking water.
Obtaining potable water in many third world countries is often difficult, due to the lack of proper water treatment facilities. The drinking of contaminated water results in serious health problems and untold number of preventable deaths. Because the development of large-scale water purification systems is an expensive undertaking, there is an extreme need for simple methodologies and devices that purify water on a small scale in a batch or single use approach, in quantities of a relatively small number of liters or less, as opposed to the more costly continuous processing systems that are commonplace in developed countries. These simple purification methodologies and devices also need to operate without any power sources, need to be easily constructed and preferably of a size that makes for easy portability, such that they can be utilized anywhere and at anytime.
Such water purification methodologies and devices can also be applied to any remote situation where potable water is not available, such as for backcountry hikers or the like. In addition, there are many situations where potable water is stored in relatively large containers or tanks over significant time periods, such as in a recreational travel vehicle or boat, for example, and these tanks may become contaminated with microbes and other undesirable biological organisms over time, damaging the quality or safety of the water and creating the need for a simple purification system.
One common solution to these problems involves the use of portable pass-through filtering systems, but such systems can be relatively costly, especially those that have sufficient antimicrobial efficiencies, and may require frequent replacement or cleaning of the filters. Furthermore, filter systems do not address the problem of microbial build-up over time in reservoir tanks or multiple use containers.
A common simple approach to purification of water is to infuse iodine, chlorine or similar soluble antimicrobial substances into the water, but these substances ruin the taste of the water and may even need to be removed prior to drinking the water by subsequent filtration if the concentrations are too high.
In the area of antimicrobials not directly related to water purification, it is known to utilize antimicrobial substances that are embedded, bound, contained, coated, etc., onto substrates. The typical systems utilize either silver-based or triclosan-based antimicrobials, and address concerns of microbe contamination or build-up on the substrates themselves. For example, it is known to embed antimicrobials into fibers that are then woven into clothing, bed linens, hospital gowns, etc., in order to preclude the growth of microbes for sanitation and odor control purposes.
A third type of antimicrobial was developed in the 1970's by Dow Corning Corporation, formerly sold under the brand SYLGARD, and is now known under the brand AEGIS MICROBE SHIELD. This silane-based antimicrobial molecule is 3-(trimethoxysilyl) propyldimethyloctadecyl ammonium chloride and has been applied to fabrics, hosiery, carpets, surgical drapes, orthopedic soft goods, aquarium filter floss, uniforms, upholstery, foams and other substrates to prevent defacement, deterioration and odor caused by microorganisms. The molecule electrostatically and covalently bonds impermanent manner to surfaces.
The silver-based and triclosan-based antimicrobials present problems for use in the purification of water for drinking purposes, since both operate by dissolving or leaching components into the water. The silver-based antimicrobials release ionic free radicals that react with cell DNA to disrupt critical life processes within the cell. The triclosan-based antimicrobials release toxic bis-chlorinated phenol (PCB) for consumption or cellular disruption, causing lethal mutations within the cell. Such systems cannot be used to create potable water. In contrast, the silane-based antimicrobial does not leach or migrate into water to destroy the microbes. Instead, the microbes are attracted to the antimicrobial by charge differential and destroyed by physical puncturing of the cell membrane.
Known uses of the silane-based AEGIS MICROBE SHIELD antimicrobial have been limited to protection of the substrates from microbial contamination and growth, even when used in water filtering applications. In other words, the antimicrobial is used to prevent microbial contamination on the filter material itself, and does not act to purify the water since the residence time of contact between the water and the antimicrobial is too short for destruction of sufficient concentrations of microbes. It has been discovered, however, that exposure of a quantity of microbe contaminated water to an efficacious amount of silane-based AEGIS MICROBE SHIELD antimicrobial incorporated on or in a substrate in a manner where it is exposed to the water will result in eradication of the microbes, provided that sufficient surface area and exposure time is present.
It is an object of this invention to provide a water purification method, system and devices which can safely and quickly purify water in batches by destroying microbes, in a manner that is easy, portable, safe and requires no power, utilizing a silane-based antimicrobial. It is a further object to provide such a water purification method, system and devices that can be utilized with either personal size containers, such as a canteen or a bottle, as well as with larger water reservoirs, such as a barrel or tank.